Multi-position thumbwheel switch assembly cylindrically arranged fixed contact rods

ABSTRACT

A stack of low-voltage thumbwheel multiposition switches may be produced from individual switches, each including a relatively flat dielectric housing defining a cavity within which is formed a cylindrical island which may be integral with one wall of the housing. A plurality of elongated electrical conductors may be located in predetermined positions within niches in the periphery of the island. The island rotatably supports an annular conductive element having a resilient spring element which may selectively be placed into contact with each of the elongated conductors, depending upon the rotational position of the annular element. A serrated surface on the periphery of the annular element may be in constant contact with a spring-biased resilient brush member which extends out of the housing for attachment to suitable circuitry. An operator may rotate the annular element by pressing his finger against the serrated periphery thereof. A plurality of such switches may be stacked one against the other, with the elongated conductors extending through all of the switches, by means of an extension on each island which may be formed integral therewith and which may be received in a complementary bore in the island of the adjacent switch.

United States Patent [1 1 Workings 1 Nov. 13, 1973 MULTI-POSITION THUMBWHEEL SWITCH ASSEMBLY CYLINDRICALLY ARRANGED FIXED CONTACT RODS [75] Inventor: John Louis Workings, Torrance,

[52] US. Cl...... 200/11 TW, 200/153 R, 200/166 B [51] Int. Cl. H0lh 19/54 [58] Field of Search 200/11 TW, 24, 17 R,

ZOO/18,153 R, 166 B [56] References Cited UNITED STATES PATENTS 11/1966 Buzzi 200/11 TW UX 5/1964 Adams 200/11 TW Primary Examiner-J. R. Scott AtwmeyWilliam H. Pavitt, Jr.

[57] ABSTRACT A stack of low-voltage thumbwheel multiposition switches may be produced from individual switches, each including a relatively flat dielectric housing defining a cavity within which is formed a cylindrical island which may be integral with one wall of the housing. A plurality of elongated electrical conductors may be located in predetermined positions within niches in the periphery of the island. The island rotatably supports an annular conductive element having a resilient spring element which may selectively, be placed into contact with each of the elongated conductors, depending upon the rotational position of the annular element. A serrated surface on the periphery of the annular element may be in constant contact with a spring-biased resilient brush member which extends out of the housing for attachment to suitable circuitry. An operator may rotate the annular element by pressing his finger against the serrated periphery thereof. A plurality of such switches may be stacked one against the other, with the elongated conductors extending through all of the switches, by means of an extension on each island which may be formed integral therewith and which may be received in a complementary bore in the island of the adjacent switch.

16 Claims, 4 Drawing Figures MULTI-POSITION TIIUMBWIIEEL SWITCH ASSEMBLY CYLINDRICALLY ARRANGED FIXED CONTACT RODS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to electrical switching devices and in particular to those of the rotary type.

2. Description of the Prior Art Rotary switches have been utilized for many years to provide a plurality of contacts about which some centrally disposed contacting member may be rotated in order to make any one of a number of possible circuit connections. A relatively early example of such a switch is disclosed and described in U.S. Pat. No. 764,218, issued July 5, 1904 to J. P. Tirrell. In this patent it may be seen that a wire is brought in and soldered or otherwise connected to each of the numerous contact positions disposed around in a circle.

In more recent years with the advent of printed circuitry, connections of this type have been more easily made, as witness U.S. Pat. Nos. 3,499,127, 3,566,049, and 3,665,127 issued to W. L. Cherry et 211., Harry D udley Wright and Joseph L. Lockard et al., respectively. However, these switches still involve bringing out the connections radially from each rotatable switch, with the necessity of making provision for connecting each of the printed circuit paths appropriately somewhere transversely of the axis about which the contact rotates. Since the contacting surfaces themselves in these switches are usually larger in area than their printed circuit paths, this may limit the number of contact point positions which can be set up particularly where an effort is made to miniaturize the switches. In addition, a further limiting factor is imposed by the fact that space is required for both the printed circuit board as well as the rotating brushing contact.

In the U.S. Pat. No. 3,284,583 issued in 1966 to U. Buzzi, providing a series of contacts about a rotating element was approached in a different manner.

Instead of bringing the connections to the various contacts our radially from each switching element, they are all passed axially through each switching'element andcollected for connection into the circuit at one end of a series of switching elements. However, one problem with the Buzzi patent arrangement lies in the. fact the rotatable members are complex in construction and would be expensive to fabricate and difficult to assemble. Also putting together the cage with the altemating stationary and rotatable discs would not appear to be a simple task.

Thus, even though the Buzzi patent has been issued for almost six years and the demands for improvements in miniaturized switching have been great even as far back as the last years, there appears to have been no practical usage of the Buzzi switch construction for miniaturized switching, or even for larger switching devices. The Buzzi approach. to rotary switching, however, does appear to offer certain advantages over other prior art multiple switches, including those employing printed circuit boards.

SUMMARY OF THE INVENTION The present invention provides a low voltage rotary switching element in which leads in the form of busbars orwires are brought in parallel to the axis of ro'tation of thecontacting member, into positions disposed in a cylindrical pattern about such axis. These leads themselves constitute the contacts. However, they are lodged in niches formed peripherally in a cylindrical insulating islandv member, the outer surfacepeaks of which consitute the bearing surface for an annular rotatable conductive member. The island member may be formed as a part of, and within a'cavity defined by a flat insulating housing comprised of an end wall and at least three side walls extending perpendicularly to the end wall. The end wall is orificed to permit the contact leads to be brought into the cavity for lodging in the niches in the island member. Since the annular conductive member is rotatably supported by the island peaks, its inner cylindrical surface does not make contact with any of the leads in the niches. In order to effect such contacting, therefore, it is desirable to provide the annular member with some type of resilient element which extends radially inwardly. Such resilient element may then move into each niche to contact the lead, or over the peaks of the insulating island. In one embodiment, a discontinuity is provided in the inner cylindrical surface of the annular member and a spring contact is incorporated into such discontinuity. Connection between the outer cylindrical surface of the annular member and a circuit may be accomplished by providing a resilient brush also within the housing cavity, within which cavity the annular conductive member rotates about the insulating and bearing supporting island. A side wall of the housing should have an opening through which a segment of the outer surface of the annular conductive member projects to permit such member to be rotated manually. Desirably, indicia are placed about the outer surface of the member to indicate which switching positions are being contacted.

This switching element lends itself readily to being stacked with other similar elements by placing the end I wall of a second switching element housing against the exposed edges of the side walls of the housing of a first switching element to close the'cavity partially defined by the walls of the housing of the first element, etc. If the orifices of the several housing walls are disposed in register, the bus-bars or wire leads may be passed .through all end walls of the stacked. housings and lodged in the niches in all co-aligned islands. Preferably the access openings to the annular members should also be co-aligned so that all of the members may be manually turned from the same side.

It will be appreciated by those persons skilled in the art that the present invention affords a switching element or stack thereof which is simple to fabricate and assemble, thereby greatly reducing the cost thereof, and further, permits an unusual degree of improved miniaturization.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings,

FIG. 1 is a side elevation of a stack of switching elements constructed in accordance with the present invention.

FIG. 2 is an enlarged section taken on the line 2-2 of FIG. I.

FIG. 3 is first view of the switching element shown in FIG. 2 taken in the direction of the arrows 3-3 in FIG. 2.

FIG. 4 is an exploded perspective view showing the components of a switching element and the manner in which they may be assembled.

DESCRIPTION OF THE PREFERRED EMBODIMENT A final assembly of a stack of low-voltage switching elements 12 may be seen in FIG. 1. Each of the elements 12 may be constructed as best shown in FIGS. and 4. A housing 14, of dielectric material, such as a ceramic, and comprised of an end wall 16 and three side walls 18, 20 and 22 serves to define a cavity 24. The ends 18a and 22a of the walls 18, 22 respectively, may be extended around partially to close the fourth side 26, leaving, however, an access space 28, the function of which will be later described.

Disposed centrally in the cavity 24 is an insulator island 30. This island 30 may either be molded with the housing walls 16, 18, 20 and 22, or it may be separately attached by means of an axial shaft'32. Whether or not the islands 30 are integrally molded with the end wall 16, the shaft 32 will serve as a means for assembling the elements 12 into the stack 10. I

The outer periphery of the island 30 comprises a series of arcuate peaks or bearing surfaces 38 between which are valleys or indentations 40, each preferably having a recess 42 in the nature of a niche. The end wall 16 of the housing 14 is provided with a series of orifices 44 in a circular pattern and registering with the island recesses or niches 42, thereby to permit elongated conductive members such as bus-bars on wires 46 to be passed through the end wall 16 and lodged in the recesses or niches 42, however, radially within the cylindrical surface 36.

The radial extremities of the bearing surfaces 38 may all be considered to be tangent to a hypothetical cylinder 36 and, similarly the wires or conductors 46 may all be considered to be tangent to a hypothetical cylinder 34 which is smaller than the hypothetical cylinder 36. As will be explained hereafter, a resilient conductive element which may be rotated about the axis of the island 30 will move, in effect, from cylinder 36, in which it contacts no wire, to cylinder 34, in which it-contacts a selected one of the wires 46.

Circumscribing the island 30 and borne by the rounded peaks 38 thereof, is an annular conductive member 50. This member 50 is preferably formed of a cylindrical sleevelike portion 52 from one end of which projects radially outwardly a serrated flange 54. Between the dimensions of the inner diameter of the sleevelike portion 52 and the fact that the peaks 38 of the island extend radially beyond the bus-bar or wires 46 when lodged in the niches 42, no contact is made between any of the bus-bars or wires 46 and the inner surface 52a of the sleevelike portion 52 of the annular conductive member 50. Contact can be made, however, by means of a resilient spring contact member 56 which is seated in an arcuate discontinuity 58 provided in the inner surface 52a of the member 50. Thus, as member 50 is rotated, element 56 will move between the hypothetical cylinders 34 and 36 as described above.

The annular member 50 is further connected into a circuit by means of a spring type brush element 60 one end 60a of which extends about a pin 61 anchored in the end wall 16 and through a slot 62 in the side wall 20 of the housing 12. The other end 60b is springbiased to maintain a continuous pressure contact upon the sinewave serrations 54a of the flange portion 54 of the annular member 50. The outer surface of the sleeve 52 should be provided with indicia such as numbers, corresponding with the various possible switching positions.

The switching element just described could be employed by itself, in which event a cover (not shown) secured by a fastener (not shown) desirably should be utilized to close the cavity 24. However, the switch construction lends itself well to a stacking or ganging of switches 10 as shown in FIG. 1. The bus-bars or wires 46 may simply be passed through the end wall 16 and lodged in the niches of the island 30 of the first switching element 12a and passed further through the end 'wall 16 of the next element 12b, etc. until each element of the stack 10 is provided with a segment of each of the common bus-bars or wires 46. The latter may be connected into a circuit through their protruding ends 46a.

In operation, it may be seen that the switches 12 may be turned to any desired numbered position by using ones thumb or other digit on that part of the flanged portion 54a of the annular element 50 which protrudes through the opening 28. The spring end 60b serves not only to make continuous brushing contact withthe an; nular conductor member 50, but it also resists any movement from the contact which is being made by spring member 56 or a bus-bar on wire 46 when the end 60b is in the particular valley 54b of the sine-wave serration. However, when it is desired to move the annular conductive element 50 to another position both the element 56 and the end 60b ride up over the peaks 38 and 54 respectively, and down into the next valleys 40 and 54b until the proper position is reached.

It may be seen from the foregoing and the accompanying drawings that by the construction of the present invention, one may obtain a very low cost, easily fabricated and assembled switching element which leads itself to miniaturization and stacking, and further may be easily connected into a circuit.

I claim:

1. A multi-position thumbwheel switching element, said element comprising:

A. A flat housing, said housing i. being contructed of a dielectric material,

ii. having side walls and at least one end wall which define a cavity, a first one of said side walls havinga discontinuity to afford access to said cavity from outside one side of the housing, and a second of said side walls having an orifice therethrough,

iii. having disposed within said cavity, spaced from the side walls partially defining the same, and attached to said end wall, an island also of a dielectric material, said island having a series of bearing surfaces disposed in a circular pattern peripherally of the island and a radially inwardly extending indentation intermediate each adjacent pair of bearing surfaces to provide a series of niches parallel to the axis of the cylinder;

iv. having its said end wall orificed with a plurality of orifices disposed in a circular pattern, each said orifice being coincident with one of the said niches;

B. A plurality of straight, elongated, conductive elements, one extending through each orifice in the orificed end wall and into said cavity to lodge in the coincident niche in the island, each said conductive element being of such diameter as not to protrude radially from its related niche to fall within a hypothetical cylinder including the adjacent bearing surfaces; and the portion of said element extending through the orifice in the end Well being connectable into a circuit;

C. An annular conductive member, said annular member having an inside diameter sufficiently greater than the diameter of the said hypothetical cylinder surface to permit said annular member to be rotatable about said bearing surfaces and bearingly supported thereby within said cavity, the inner surface of said annular member being recessed for a predetermined arcuate distance, and an arcuate segment of the outer surface of said annular member being accessible from outside of said housing through the discontinuity in said first side wall thereof;

D. A spring element, said springelement being of conductive metal and seated in the recess in the inner surface of said conductive annular member, said spring element including a portion resiliently projecting radially inwardly, whereby as the-annular member is rotated about the island, said projecting portion of the spring element alternately extends into a niche to contact the conductive element lodged therein, or rides up over an adjacent bearing surface to break the contact between the conductive element in the niche and said portion of the spring element; and v E. A conductive brush, said brush having a portion disposed within said cavity and maintained in continuous slidable contact with the outer surface of the annular conductive metal member, and another portion extending through the orifice in the second side of said wall of the housing for connection into an electrical circuit. r

2. A stack of thumbwheel switches, said stack coniprising a plurality of similar multi-position thumbwheel switching elements each of said elements being as described in claim I and disposedin identical orientation with the end wall of the housing of each element, after thefirst in the stack, being disposed in abutment with the edges of side walls of another element to close its cavity, and with the orifices of all of said end walls being in register; an end wall closing the cavity of the last element in the stack, said end wall being secured to the side walls of said last element; and the plurality of elongated conductive elements for each switching element being common to all others, with the ends thereof protruding from the orifices in the end wall of the said first element of the stack for electrical connection into a circuit.

3. The stack of thumbwheel switches as described in claim 2, wherein one elongated conductive element is eliminated from insertion through one of the series of registering orifices in the end walls of the element and lodging into the coincident niches in all of the islands, thereby providing all of the switching elements with at least one non-contact position.

4. A multi-position switching element as described in claim 1, wherein the annular conductive member includes a cylindrical portion upon which indicia are provided to indicate the' relative angular, and hence switching, position thereof.

- 5. A multi-position switching element as described in claim 4, wherein the annular conductive member also includes a radiating flange to facilitate turning thereof by a-thumb or other digit.

6. A multi-position switching element as described in claim 1, wherein the housing and island are integrally formed of a ceramic material.

7. A multi-position switching element as described in claim 1, wherein the cavity is substantially annular about the island.

8. Amulti-position switching element as described in claim 1 wherein the conductive brush is a resilient spring element one end of which presses against the outer surface of the annular member at all times.

9. A multi-position switching element as described in claim 1, wherein the bearing surfaces of the island are arcuate, with the axes of the arcs being parallel to the axis of the island itself, thereby to provide good bearing surfaces to support the rotatable annular element;

10. A multi-position switching'element as described in claim 9, wherein each indentation comprises an arcuate segment extending between the bases of the arcuate bearing surfaces, and each segment is further recessed to receive one of the conductive elements.

11. A rotary switch, said switch having a series of radially outwardly facing contacts disposed in a first hypothetical cylinder about an axis, each of said contacts being spaced and insulated from adjacent contacts by dielectric members radiating between said contacts and terminating in ends lying in a second hypothetical cylinder; a dielectric housing maintaining such contacts and dielectric members in such disposition and affording electrical connections to such contacts from an external circuit; an annular contact member bearingly supported by the ends of said dielectric members in said second hypothetical cylinder for rotation thereabout, said annular contact member having a radially inwardly extending resilient element adapted to move alternately, as the annular member is rotated about the second hypothetical cylinder to make an electrical connection with one of said contacts, to a second position in the second hypothetical cylinder at the end of one of said dielectric members, thereby to break electrical connection with all of said contacts; and brush means, said brush means having one end maintained in continuous brushing contact with the annular member and its other end being connectable to an external circuit.

12. A rotary switch as described in claim 11, wherein said contacts extend are made through said housing parallel to said axis.

13. A rotary switch as described in claim 11, wherein the annular contact member includes a cylindrical sleeve portion and a serrated flange portion, said flange portion protruding, in part, out of said housing for manual rotation of said annular contact member, and the brush means includes a resilient arm which is disposed transversely of the said axis to ride over the serrations in said flange portion, the last said arm located between adjacent teeth on said serrated flange when the resilient element of said annular member is extended into said first hypothetical cylinder, thereby inhibiting said resilient element from being inadvertently moved out of electrical connection with the particular contact with which it is in contact.

14. A switching device comprising means for insulatingly supporting a plurality of conductors in predetermined positions parallel to and about an axis and for insulatingly supporting an annular conductive member for rotation about said axis,

.a plurality of conductors located in predetermined positions parallel to and about said axis on said supporting means,

an annular conductive member rotatably mounted on said supporting means and electrically separated from said plurality of conductors and including contact means for contacting one of said plurality of conductors at a time, in accordance with the rotational position of said conductive member about said axis, to selectively form an electrically conductive path from the one of said plurality of conductors to said annular conductive member, and

brush means in electrical wiping contact with the periphery of said annular conductive member to continue the electrical path from the one of said pluraling means for electrically insulating adjacent annular conductive members and their related contact means. 

1. A multi-position thumbwheel switching element, said element comprising: A. A flat housing, said housing i. being contructed of a dielectric material, ii. having side walls and at least one end wall which define a cavity, a first one of said side walls having a discontinuity to afford access to said cavity from outside one side of the housing, and a second of said side walls having an orifice therethrough, iii. having disposed within said cavity, spaced from the side walls partially defining the same, and attached to said end wall, an island also of a dielectric material, said island having a series of bearing surfaces disposed in a circular pattern peripherally of the island and a radially inwardly extending indentation intermediate each adjacent pair of bearing surfaces to provide a series of niches parallel to the axis of the cylinder; iv. having its said end wall orificed with a plurality of orifices disposed in a circular pattern, each said orifice being coincident with one of the said niches; B. A plurality of straight, elongated, conductive elements, one extending through each orifice in the orificed end wall and into said cavity to lodge in the coincident niche in the island, each said conductive element being of such diameter as not to protrude radially from its related niche to fall within a hypothetical cylinder including the adjacent bearing surfaces; and the portion of said element extending through the orifice in the end wall being connectable into a circuit; C. An annular conductive member, said annular member having an inside diameter sufficiently greater than the diameter of the said hypothetical cylinder surface to permit said annular member to be rotatable about said bearing surfaces and bearingly supported thereby within said cavity, the inner surface of said annular member being recessed for a predetermined arcuate distance, and an arcuate segment of the outer surface of said annular member being accessible from outside of said housing through the discontinuity in said first side wall thereof; D. A spring element, said spring element being of conductive metal and seated in the recess in the inner surface of said conductive annulAr member, said spring element including a portion resiliently projecting radially inwardly, whereby as the annular member is rotated about the island, said projecting portion of the spring element alternately extends into a niche to contact the conductive element lodged therein, or rides up over an adjacent bearing surface to break the contact between the conductive element in the niche and said portion of the spring element; and E. A conductive brush, said brush having a portion disposed within said cavity and maintained in continuous slidable contact with the outer surface of the annular conductive metal member, and another portion extending through the orifice in the second side of said wall of the housing for connection into an electrical circuit.
 2. A stack of thumbwheel switches, said stack comprising a plurality of similar multi-position thumbwheel switching elements each of said elements being as described in claim 1 and disposed in identical orientation with the end wall of the housing of each element, after the first in the stack, being disposed in abutment with the edges of side walls of another element to close its cavity, and with the orifices of all of said end walls being in register; an end wall closing the cavity of the last element in the stack, said end wall being secured to the side walls of said last element; and the plurality of elongated conductive elements for each switching element being common to all others, with the ends thereof protruding from the orifices in the end wall of the said first element of the stack for electrical connection into a circuit.
 3. The stack of thumbwheel switches as described in claim 2, wherein one elongated conductive element is eliminated from insertion through one of the series of registering orifices in the end walls of the element and lodging into the coincident niches in all of the islands, thereby providing all of the switching elements with at least one non-contact position.
 4. A multi-position switching element as described in claim 1, wherein the annular conductive member includes a cylindrical portion upon which indicia are provided to indicate the relative angular, and hence switching, position thereof.
 5. A multi-position switching element as described in claim 4, wherein the annular conductive member also includes a radiating flange to facilitate turning thereof by a thumb or other digit.
 6. A multi-position switching element as described in claim 1, wherein the housing and island are integrally formed of a ceramic material.
 7. A multi-position switching element as described in claim 1, wherein the cavity is substantially annular about the island.
 8. A multi-position switching element as described in claim 1, wherein the conductive brush is a resilient spring element one end of which presses against the outer surface of the annular member at all times.
 9. A multi-position switching element as described in claim 1, wherein the bearing surfaces of the island are arcuate, with the axes of the arcs being parallel to the axis of the island itself, thereby to provide good bearing surfaces to support the rotatable annular element.
 10. A multi-position switching element as described in claim 9, wherein each indentation comprises an arcuate segment extending between the bases of the arcuate bearing surfaces, and each segment is further recessed to receive one of the conductive elements.
 11. A rotary switch, said switch having a series of radially outwardly facing contacts disposed in a first hypothetical cylinder about an axis, each of said contacts being spaced and insulated from adjacent contacts by dielectric members radiating between said contacts and terminating in ends lying in a second hypothetical cylinder; a dielectric housing maintaining such contacts and dielectric members in such disposition and affording electrical connections to such contacts from an external circuit; an annular contact member bearingly supported by the ends of said dielectric members in said second Hypothetical cylinder for rotation thereabout, said annular contact member having a radially inwardly extending resilient element adapted to move alternately, as the annular member is rotated about the second hypothetical cylinder to make an electrical connection with one of said contacts, to a second position in the second hypothetical cylinder at the end of one of said dielectric members, thereby to break electrical connection with all of said contacts; and brush means, said brush means having one end maintained in continuous brushing contact with the annular member and its other end being connectable to an external circuit.
 12. A rotary switch as described in claim 11, wherein said contacts extend are made through said housing parallel to said axis.
 13. A rotary switch as described in claim 11, wherein the annular contact member includes a cylindrical sleeve portion and a serrated flange portion, said flange portion protruding, in part, out of said housing for manual rotation of said annular contact member, and the brush means includes a resilient arm which is disposed transversely of the said axis to ride over the serrations in said flange portion, the last said arm located between adjacent teeth on said serrated flange when the resilient element of said annular member is extended into said first hypothetical cylinder, thereby inhibiting said resilient element from being inadvertently moved out of electrical connection with the particular contact with which it is in contact.
 14. A switching device comprising means for insulatingly supporting a plurality of conductors in predetermined positions parallel to and about an axis and for insulatingly supporting an annular conductive member for rotation about said axis, a plurality of conductors located in predetermined positions parallel to and about said axis on said supporting means, an annular conductive member rotatably mounted on said supporting means and electrically separated from said plurality of conductors and including contact means for contacting one of said plurality of conductors at a time, in accordance with the rotational position of said conductive member about said axis, to selectively form an electrically conductive path from the one of said plurality of conductors to said annular conductive member, and brush means in electrical wiping contact with the periphery of said annular conductive member to continue the electrical path from the one of said plurality of conductors to a circuit.
 15. The device of claim 14 wherein said annular conductive member includes serrations on the periphery thereof and said brush means includes a spring-biased portion thereof which cooperates with said serrations to inhibit movement of said annular conductive member about said axis while simultaneously forming the continuation of said electrical path.
 16. A plurality of switching devices, each as described in claim 15, wherein the said plurality of conductors are common to all of said switches and including means for electrically insulating adjacent annular conductive members and their related contact means. 